I've had my 757c since 2008 and it has worked great.  Hit the lake two weeks ago and the GPS isn't working.  I dismounted it, made sure all the connections were clean, made sure everything was tight, but it's still not working.  Nothing has really changed.  When I run the test it says not connected.  Trying to figure out if it the unit or the GPS puck.  
Do the GPS pucks fail?  There really isn't a lot to them so I'm not sure what could have changed.  
Any advice other than sending it in?